Question: $ { \left[\begin{array}{r}{2} \\ {1} \\ {3}\end{array}\right]+\left[\begin{array}{r}{-1} \\ {-2} \\ {0}\end{array}\right] = {?} } $
To find the sum of two matrices, add the corresponding items between each matrix. ${\left[\begin{array}{r}{2}+{-1} \\ {1}+{-2} \\ {3}+{0}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{1} \\ {-1} \\ {3}\end{array}\right]}$